2. With that new layer active, use the colour select tool , bump the threshold up to around approx. the 80 mark. Click in the canvas on a black area to select all the black. You should have those 'crawling ants' showing. https://i.imgur.com/hXYobpL.jpg

Are they faint because they are grey instead of black? Or faint because they are too small?

Can you post a representative sample of the document.

It is there. Rich2000 posted it. See his link there? Or failing that my document in the thread up there - that is the text I'm talking about. It has been rearranged but that's it. How to darken it? Some printers, some paper, some children's eyesight and diligence it is good enough, others not so.

Edit:
Woops.... I just posted this and then I see Rich2000 posted an answer himself. Why didn't it show up when I first looked? Doesn't matter. I will now go and read it.... sorry....

Further Edit:

O.K., thankyou Rich, I'll get onto it and report how I go. I know it is called a text layer but surely that's not really text in my document? It was a scanned (photographed) image I started with. I didn't construct the document using text fonts from Gimp. And I think you used my original or did you construct from the beginning? I didn't know...

Final Edit: Well I've done it. Worked beautifullly and easily thanks to the excellent and painstaking guidance for which I owe many thanks. Thank you.

I didn't print out yet but I can see it will do the job and of course if it doesn't suit I now know what to do. But it will.